Hydraulic cylinders in the automotive repair and maintenance industry have been used for decades. Their ability to deliver large amounts of pressing or pulling force while still being fairly portable makes them one of the most used devices in a vehicle repair shop. They are often used together with various extracting and mounting tools, especially with components that are fitted in slots using large pressing forces, e.g. wheel bearings, wheel hubs, axle shafts, etc.
Even though most of the tools used in repair shops have evolved quite a bit in terms of size, weight and simplicity, hydraulic cylinders still to this day are pretty much the same hydraulic cylinders that were used decades ago, aside for some smaller improvements. And due to the fact that there are relatively large forces involved, there have been few attempts to provide a small and light hydraulic cylinder without using unreasonably expensive and scarce materials. However, with the ever present need to reduce size and optimize the space usage in every aspect of the automotive industry there is a rapidly growing need for a similar evolution in the automotive repair industry as well, in particular for hydraulic cylinders.
Single acting hydraulic cylinders are often preferable over double acting hydraulic cylinders in terms of simplicity and cost. Their general configuration allows them to be used for pulling action at one end, and pressing action at the other end. However, as mentioned the demand for size reduction and/or space optimization in all aspects of the automotive industry has lately become rather problematic. Particularly when using the hydraulic cylinder in a so called pressing mode the operator (mechanic) often has to work in extremely confined spaces which can cause a lot of problems when it comes to adjusting the position of for example the press axle or pressing rod.
To this end some attempts have been made to solve some of the abovementioned issues, like for example providing a hydraulic cylinder with a hollow piston rod and a press axle/pressing rod that extends over the entire axial length of the hydraulic cylinder, such as cylinder is e.g. described in US 2006/0196029. However, this solution is limited in many ways, and greatly increases the risk of bending the pressing rod inside the cylinder housing which often results in both costly and complicated repairs of the actual hydraulic cylinder.
There is therefore a need for an improved hydraulic cylinder for use in auto repair shops, which is compact, light and easy to operate.